Systems and Methods for Edge Measurement

ABSTRACT

A method for straightening the edges of a work piece. The method includes the steps of determining the average edge position of each edge of the work piece, calculating an average edge line for each edge of the work piece, determining an actual corner point for each corner of the work piece, calculating a determined edge line through each of the actual corner points of the work piece, determining a number of actual edge points, determining if actual edge points are within the determined edge lines, and adjusting the determined edge lines inward until the actual edge points are within the determined edge lines.

TECHNICAL FIELD

The present application relates generally to systems and methods forwork piece edge detection and measurement and more particularly relatesto systems and methods for finishing the edges of a textile or carpetingwork piece in an accurate and efficient manner.

BACKGROUND OF THE INVENTION

Although numerous attempts have been made to automate the finishingprocess for textiles, carpeting, and similar materials, these attemptshave not always been successful with respect to quality control and/orwith respect to production time because of the general lack ofuniformity in the work piece. For example, rugs may be cut by variousmeans and have all types of variances therein. The width, length, andangles of the corners all may vary from piece to piece. The edgesthemselves may be cut with a bow or a crooked wave therein. Knownautomated systems that only accommodate the general length and the widthof the work piece may not be able to accommodate these variations. Theresult thus may be an inefficient cutting at best or a damaged orrejected work piece.

There is a desire therefore for systems and methods for accommodatingnon-uniform work pieces in an automated finishing system. The systemsand methods should be able to adapt to even minor variations in the workpiece in a high speed and efficient manner.

SUMMARY OF THE INVENTION

The present application thus describes a method for straightening theedges of a work piece. The method may include determining the averageedge position of each edge of the work piece, calculating an averageedge line for each edge of the work piece, determining an actual cornerpoint for each corner of the work piece, determining a number of actualedge points, calculating a determined edge line through each of theactual corner points of the work piece, determining if the number ofactual edge points are within the determined edge lines, and adjustingthe determined edge lines inward until the number of actual edge pointsare within the determined edge lines.

The method further may include taking an image of the work piece andevaluating that image with a blob tool. The method further may includedetermining an outline of the image of the work piece.

The step of determining the average edge position of each edge of thework piece may include evaluating the image of the work piece with edgedetection tools. The step of determining an actual corner point for eachcorner of the work piece may include evaluating the image of the workpiece with edge detection tools. The step of determining a number ofactual edge points may include evaluating the image of the work piecewith edge detection tools.

The method further may include the step of adjusting the determined edgelines inward. The adjusting step is repeated until the number of actualedge points is within the determined edge lines and a number of finaledge lines are calculated. The method further may include the step ofrouting the final edge lines to a maneuvering system. The final edgelines may include the final angles. The work piece then may be finishedaccording to the number of final edge lines.

The present application further describes a finishing system for a workpiece. The finishing system may include a sewing head, a visual sensorfor taking an image of the work piece, and a number of edge positioningtools for determining an actual corner point for each corner of the workpiece and for determining a number of actual edge points for each edgeof the work piece. The system further includes calculating means todetermine a number of determined edge lines through the actual cornerpoints and to determine if any of the number of actual edge points areoutside the number of determined edge lines so as to create a number offinal edge lines outside of the number of actual edge points. The systemalso includes a maneuvering system for maneuvering the work piecethrough the sewing head such that the work piece is finished along thenumber of final edge lines.

The maneuvering system may include a gantry arm assembly with atemplate. The visual sensor may include a blob tool. The number of finaledge lines may include an equilateral shape.

The present application further describes a method for straightening theedges of a work piece. The method may include determining an actualcorner point for each corner of the work piece, determining a number ofactual edge points, calculating a determined edge line through each ofthe actual corner points of the work piece, determining if the number ofactual edge points are within the determined edge lines, and adjustingthe determined edge lines inward until the number of actual edge pointsare within the determined edge lines. The adjusting step is repeateduntil the number of actual edge points is within the determined edgelines and a number of final edge lines are calculated.

These and other features of the present application will become apparentto one of ordinary skill in the art upon review of the followingdetailed description when taken in conjunction with the several drawingsand the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a finishing apparatus as is describedherein.

FIG. 2 is a flowchart showing the finishing methods as are describedherein.

FIG. 3 is a plan view of a work piece as seen by the system describedherein.

FIG. 4 shows the use of edge detection tools with the work piece todetermine the average edge position.

FIG. 5 shows the average edge line for each edge of the work piece.

FIG. 6 shows the use of edge detection tools to determine the actuallocation of the corner points.

FIG. 7 shows the determination of actual edge points of the edges of thework piece with edge detection tools.

FIG. 8 shows the calculation of each true corner point.

FIG. 9 shows the adjustments in the determined edge lines to accommodatethe actual edge points (exaggerated).

FIG. 10 shows the final work piece.

DETAILED DESCRIPTION

Referring now to the drawings in which like numerals refer to likeelements throughout the several views, FIG. 1 shows a schematic view ofa finishing system 100. The finishing system 100 is used to finish theedges of a work piece 110 in a conventional manner. The work piece 110may be any type of textile, carpeting, or similar type of woven productof any shape or dimension. The work piece 110 may be cut from acontinuous source of material. Each work piece 110 has a number ofcorners 115 and edges 120. The finishing system 100 includes a tabletop125. The tabletop 125 may be any type of substantially flat surface ofany dimension. The work piece 110 is maneuvered along the tabletop 125.

Mounted on the tabletop 125 may be a sewing head 130. The sewing head130 may be of conventional design. For example, sewing heads made byPegasus of Singapore and sold under the designations EX5204-24 andEX5203-25. Other examples include sewing heads sold by Union Special ofHuntley, Ill. under the designation “Model 56300G”. JUKI Corporation ofTokyo, Japan also sells a flat bed sewing head. Similar types of devicesmay be used herein. More than one sewing head 130 may be used. Further,more than one type of sewing head 130 also may be used for versatilityin accommodating different types of work pieces 110.

The finishing system 100 further includes a maneuvering system 140. Themaneuvering system 140 may be of conventional design. The maneuveringsystem 140 may be any type of device that can maneuver the work piece110 across the tabletop 125 or otherwise. In this example, themaneuvering system 140 may take the form of a gantry arm assembly 150with a template 160 or similar types of device. The gantry arm assembly150 allows the template 160 to move in the X and Y directions. Likewise,the template 160 may maneuver in the Z direction as desired. An exampleof a maneuvering system 140 is shown in U.S. Pat. No. 5,619,942,entitled “Method And Apparatus For Finishing The Edges Of A TextileProduct.” U.S. Pat. No. 5,619,942 is incorporated herein by reference.

The finishing system 100 further may include a number of visual sensors170. The visual sensors 170 may be mounted on the maneuvering system 140or they may be free standing. The visual sensors 170 may take the formof cameras, photo optical devices, Examples include sensors sold byCognex Corporation of Natick, Mass. under the designations of “Model5000” and “DVT”. Similar types of devices may be used herein. More thanone type of visual sensor 170 may be used

A programmable controller 180 may control operation of the components ofthe finishing system 100 as a whole. The controller 180 may be aconventional microprocessor or a similar type of programmable device.For example, a PMAC controller sold by Delta Tau Data Systems ofHayward, Calif. and similar types of devices may be used herein.

It is important to note that the finishing system 100 described above isby way of example only. The edge detection techniques described belowcan be used with many different types of finishing systems such that thescope of the invention is in no way limited to the use of the finishingsystem 100 described herein.

FIG. 2 is a flowchart showing the various steps in the edge positioningmethods described herein. The steps of the flowchart relate toprogramming steps that can be embodied in conventional software code byone of ordinary skill in the art, i.e., these steps may be embodied in acomputer-readable medium having computer-executable instructions in anyconventional programming language.

FIG. 3 shows the first step, a rough outline step 190. Specifically, thevisual sensor 170 determines the outline of the work piece 110. Thevisual sensor 170 may take a picture of the work piece 110. That picturethen may be evaluated by a blob tool so as to define the edges of thework piece. A blob tool detects changes in pixels such that a generaloutline of an object in a region of interest may be determined . Blobtool software is available, by way of example, through CognexCorporation of Natick, Mass. Other types of visual interpretationsoftware and means may be used herein.

The next step is an edge detection step 200. As is shown in FIG. 4, edgedetection tools 210 are applied to the general outline produced by themeasurements of the blob tool. The edge detection tools 210 determinethe average position of each edge 120 so as to calculate an average edgeline 220 for each edge. The edge detection 210 tools are part of theblob tool software packages described above. Other types of visualinterpretation software and means may be used herein. The overlap in theaverage edge lines 220 is used in an intersection calculation step 230.The intersection of the average edge lines 220 thus is calculated anddetermined as is shown in FIG. 5.

A number of actual corner points 240 are then found in an actual cornerdetection step 250 shows in FIG. 6. As is shown, the edge detectiontools 210 are placed at the image of each corner to find the actuallocation of each actual corner point 240.

The next step is an actual edge detection step 260. As is shown in FIG.7, edge detection tools 210 are placed along the sides of the image ofthe work piece 110 so as to locate a number of actual edge points 270along the respective edges. The actual edge points 270 generally includeminimum and maximum point locations along the edges. Based upon thisdetermination, a determined edge line 280 through each of the actualcorner points 240 is found in step 290 and shown in FIG. 8.

The next step is an evaluation step 300. The actual edge points 270 areevaluated to determine if any are outside of the determined edge lines280. If so, the determined edge lines 280 are adjusted inward at step310 as is shown in exaggerated form in FIG. 9. The start of the edge atthe actual corner point 240 remains fixed. The determined edge lines 280are adjusted until all of the actual edge points 270 are within thedetermined edge lines 280 and a final shape is produced.

Once all of the actual edge points 270 are within the adjusteddetermined edge line 280, a number of final edge lines 320 arecalculated. These final edge lines 320, including length and angle, aresent to the maneuvering system 140 in a routing step 330. As is shown inFIG. 10, the result is a work piece outline with four edge lines thatare guaranteed to be within the work piece 110. These coordinates arethen sent to the controller 180 along with the width, location, andangle for the finishing system 100 to use to move the work piece 110along the tabletop 125 and the sewing head 130.

The systems and methods described herein thus produce a finished workpiece 110 with uniform sides regardless of any imperfections in theoriginal piece. Further, the system and methods described hereinoptimize the sewing paths such that the sewing is always on the edge ofthe work piece 110.

It should be apparent that the foregoing relates only to the preferredembodiments of the present application and that numerous changes andmodifications may be made herein by one of ordinary skill in the artwithout departing from the general spirit and scope of the invention asdefined by the following claims and equivalents thereof.

1. A method for straightening the edges of a work piece, comprising:determining the average edge position of each edge of the work piece;calculating an average edge line for each edge of the work piece;determining an actual corner point for each corner of the work piece;determining a plurality of actual edge points; calculating a determinededge line through each of the actual corner points of the work piece;determining if the plurality of actual edge points are within thedetermined edge lines; and adjusting the determined edge lines inwarduntil the plurality of actual edge points are within the determined edgelines.
 2. The method of claim 1, further comprising taking an image ofthe work piece.
 3. The method of claim 2, further comprising evaluatingthat image with a blob tool.
 4. The method of claim 2, furthercomprising determining an outline of the image of the work piece.
 5. Themethod of claim 2, wherein the step of determining the average edgeposition of each edge of the work piece comprises evaluating the imageof the work piece with edge detection tools.
 6. The method of claim 2,wherein the step of determining an actual corner point for each cornerof the work piece comprises evaluating the image of the work piece withedge detection tools.
 7. The method of claim 2, wherein the step ofdetermining a plurality of actual edge points comprises evaluating theimage of the work piece with edge detection tools.
 8. The method ofclaim 2, further comprising the step of adjusting the determined edgelines inward.
 9. The method of claim 1, wherein the adjusting step isrepeated until the plurality of actual edge points are within thedetermined edge lines and a plurality of final edge lines arecalculated.
 10. The method of claim 9, further comprising the step ofrouting the final edge lines to a maneuvering system.
 11. The method ofclaim 9, wherein the calculating the final edge lines comprisescalculating the final angles.
 12. The method of claim 10, furthercomprising finishing the work piece according to the plurality of finaledge lines.
 13. A finishing system for a work piece, comprising: asewing head; a visual sensor for taking an image of the work piece; aplurality of edge positioning tools for determining an actual cornerpoint for each corner of the work piece and for determining a pluralityof actual edge points for each edge of the work piece; calculating meansto determine a plurality of determined edge lines through the actualcorner points and to determine if any of the plurality of actual edgepoints are outside the plurality of determined edge lines so as tocreate a plurality of final edge lines outside of the plurality ofactual edge points; and a maneuvering system for maneuvering the workpiece through the sewing head such that the work piece is finished alongthe plurality of final edge lines
 14. The finishing system of claim 13,wherein the maneuvering system comprises a gantry arm assembly.
 15. Thefinishing system of claim 13, wherein the gantry arm assembly comprisesa template.
 16. The finishing system of claim 13, wherein the visualsensor comprises a blob tool.
 17. The finishing system of claim 13,wherein the plurality of final edge lines comprise an equilateral shape.18. A method for straightening the edges of a work piece, comprising:determining an actual corner point for each corner of the work piece;determining a plurality of actual edge points; calculating a determinededge line through each of the actual corner points of the work piece;determining if the plurality of actual edge points are within thedetermined edge lines; and adjusting the determined edge lines inwarduntil the plurality of actual edge points are within the determined edgelines.
 19. The method of claim 18, wherein the adjusting step isrepeated until the plurality of actual edge points are within thedetermined edge lines and a plurality of final edge lines arecalculated.